The top LB agarose (0.7%) of 3 mL maintained in molten (47 ํC) condition was added, mixed and poured onto LB agar plates, allowed to set and incubated for 6-8 h at 37 ํC. The phage was recovered by adding 3 mL of SM buffer to each plate and the plates were stored at 4-8 ํC for several hours with gentle shaking on rocking platform to allow bacteriophage to diffuse from the agarose. SM buffer containing phage particles was transferred to a polypropylene tube, 0.2 mL of chloroform was added and again 2 mL of SM buffer was also added. The lysate was drained to recover the maximum phage particles. The mixture was gently vortexed, then centrifuged at 4000 x g for 15 min at 4-8 ํC. The supernatant was aspirated, a drop fo chloroform was added, and the phage suspension was stored at 4-8 ํC. The titres of phage stocks were determined by plaquing 10-fold dilutions by the soft agarose overlay method.